Valve for filling bottles with pressurized drinks

In a back pressure filling valve for bottles designed for containing pressurized drinks, wherein the bottles are filled from a tank having a bottom wall and containing a liquid and a gas under pressure, comprising, a tubular casing element fixed to and extending through the bottom wall of said tank and having openings within the tank for the passage of liquid, a valve body member having a cylindrical portion slidably mounted in said tubular casing element and having uppper and lower tubular portions extending above and below said cylindrical portion, respectively, a ventilation tube slidably mounted in said upper tubular portion and extending below said lower tubular portion, the inner wall of said lower tubular portion being of greater diameter than that of the ventilation tube, providing an annular cavity therebetween, an elastomeric check valve mounted on said valve body member and having a frusto-conical portion engageable with said ventilation tube, an annular cylindrical body member mounted on the lower end of said tubular casing, a diaphragm valve member mounted at its outer circumference on said annular cylindrical body member and having a central concentric opening slidably engaging the lower tubular portion of the valve body member, said annular cylindrical body member having a frusto-conical surface beneath said diaphragm valve member and engageable thereby in the open position of said valve member, said ventilation tube having orifices above said elastomeric check valve whereby said check valve controls fluid flow through said orifices.